package com.ccp.dev.system.util;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/**
 * 生成验证码工具类
 * @author web
 */
public class RandomValidateCodeUtil {
    /**
     * 放到session中的key
     */
    public static final String RANDOM_CODE_KEY = "RANDOM_VALIDATE_CODE_KEY";
    /**
     * 随机产生只有数字的字符串
     */
    // private String randString = "0123456789";
    /**
     * 随机产生只有字母的字符串
     */
    // private String //private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /**
     * 随机产生数字与字母组合的字符串
     */
    private String randString = "123456789ABCDEFGHJKMNPQRSTUVWXYZ";
    /**
     * 图片宽
     */
    private int width = 95;
    /**
     * 图片高
     */
    private int height = 25;
    /**
     * 干扰线数量
     */
    private int lineSize = 40;
    /**
     * 随机产生字符数量
     */
    private int stringNum = 4;

    private Random random = new Random();

    /**
     * 获得字体
     */
    private Font getFont() {
        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
    }
    /**
     * 获得颜色
     */ private Color getRandColor(int fc, int bc){
         if(fc > 255){
             fc=255;
         }
         if(bc > 255){
             bc =255;
         }
        int r = fc + random.nextInt(bc - fc - 16);
        int g = fc + random.nextInt(bc - fc - 14);
        int b = fc + random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }
    /**
     * 生成随机图片
     */
    public void getRandcode(HttpServletRequest request, HttpServletResponse response){
        HttpSession session = request.getSession();
        /*
         BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
          */
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
        /*
         产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
         */
        Graphics g = image.getGraphics();
        /*
         图片大小
         */
         g.fillRect(0, 0, width, height);
         /*
         字体大小
         */
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
        /*
         字体颜色
         */
        g.setColor(getRandColor(110, 133));
        /*
         绘制干扰线
         */
        for(int i=0;i<=lineSize;i++){
            drownLine(g);
        }
        /*
         * 绘制随机字符
         */
        String randomString = "";
        for (int i = 1; i <= stringNum; i++) {
            randomString = drowString(g, randomString, i);
        }
        /*
        将生成的随机字符串保存到session中
         */
        session.removeAttribute(RANDOM_CODE_KEY);
        session.setAttribute(RANDOM_CODE_KEY, randomString);
        g.dispose();
        try {
            /*
            将内存中的图片通过流动形式输出到客户端
             */
            ImageIO.write(image, "JPEG", response.getOutputStream());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /**
     * 绘制字符串
     */
    private String drowString(Graphics g, String randomString, int i) {
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random .nextInt(121)));
        String rand = String.valueOf(getRandomString(random.nextInt(randString .length())));
        randomString += rand;
        g.translate(random.nextInt(3),
                random.nextInt(3));
        g.drawString(rand, 13 * i, 16); return randomString;
    }
    /**
     * 绘制干扰线
     */ private void drownLine(Graphics g) {
         int x = random.nextInt(width);
         int y = random.nextInt(height);
         int xl = random.nextInt(13);
         int yl = random.nextInt(15);
         g.drawLine(x, y, x + xl, y + yl);
     }

    /**
     * 获取随机的字符
     */
    public String getRandomString(int num) {
        return String.valueOf(randString.charAt(num));
    }
}
